Question

Suppose an isosceles triangle ABC has A = 45° and b = c = 3. What is the length of a2? A. 12.73 B. 5.27 C. 2.30 D. 30.73

Answer 1

Given that A=45 and b=c=3, to get the value of a we use the cosine rule;
a^2=b^2+c^2-2bcCosA
thus;
a^2=3^2+3^2-2*3*3cos45
a^2=9+9-18cos 45
a^2=18-18cos45
a^2=5.2721
thus;
a=sqrt5.2721
a=2.296-=2.3
The answer is C. 2.3